Was there any resolution to what this sound is on our cars? From what I have read, it sounds like this may be the VANOS versus the videos of the loud sound at startup, which is something more serious. If it's the VANOS, is it a major concern or something that can be lived with for years, and miles, to come?

I have a 2007 E92 M3 with about 38000 miles. When starting the engine from cold there is a loud noise like a mechanical knocking or rattling which goes away within a couple of seconds. This has developed over the last 2000 miles.

Little bit of an update on mine. Like I said, mine doesn't do it unless I stop driving it every day. So I'd suggest people who DD think about letting it sit for a couple of days and then listen for this.

It is a real problem. My dealer acknowledged the problem after letting it sit for 2 days and starting it. They have contacted BMW asking how to proceed. I'll update when I know more.

BMW will be replacing both timing chain tensioners on my car this week. Apparently, it is not a problem with the VANOS system because they disconnected the VANOS solenoid (Iirc) and the noise was still present.

BMW will be replacing both timing chain tensioners on my car this week. Apparently, it is not a problem with the VANOS system because they disconnected the VANOS solenoid (Iirc) and the noise was still present.

Sounds like the same route they took with mine...in my case, that didnt work. Hope it does for yours!

I live in Germany...... If you want to believe it is a 2007..... cool. But read the following and see if you still believe.

"The fourth generation BMW M3 was announced on the 2007 Geneva Auto Show (Switzerland, March 6-18th, 2007) with the BMW M3 concept. As was the case with the E46 M3 Concept and E60 M5 Concept, the M3 Concept hid almost nothing of the looks of the production version, that had its world premiere on the 2007 Frankfurt Auto Show IAA (Germany, September 13 to 23rd). It was originally set to be called M4 along with 3 Series coupes and convertibles which were to become the 4 Series, but due to the interest in retaining the M3 bloodline, this was scrapped and the lineup continued as it is."

Production in Sept of 2007 is a 2008 model. Mine was built in April of 2010 and it is a 2011 model.... trackin???

get a life, the man asked about an engine noise, not year his car was built. if you don't have input towards the thread keep it to yourself.

the engine noise can be lack of lubrication to the lifters, it very common, even more so with M3's in 6MT.

I personally believe that it sounds like timing chain slap. There are valves on the hydraulic timing chain tensioners that hold in oil pressure to keep the chain tight while the engine is off. If the valves on the tensioners go bad, the oil pressure will bleed off allowing the chain to become a little loose. When the engine first starts and oil pressure is low, the chain will rattle until oil pressure builds up and reapplies pressure to the tensioners and chain.

BMW seems to agree. They are changing my timing chain tensioners as we speak. However, another member posted that this didn't solve his problem. In one case, replacing the VANOS check valves seemed to do the trick but that didn't work in another. From what I understand, there are pins on the VANOS that lock the system in place when the engine is off in which case the check valves don't come into play at start up. Again, my dealer/BMW seems to agree with this. They disabled the VANOS system (disconnected the VANOS solenoid IIRC?) and the problem was still present.

edit: I should also mention that nothing suggests that this is a bearing issue.

I personally believe that it sounds like timing chain slap. There are valves on the hydraulic timing chain tensioners that hold in oil pressure to keep the chain tight while the engine is off. If the valves on the tensioners go bad, the oil pressure will bleed off allowing the chain to become a little loose. When the engine first starts and oil pressure is low, the chain will rattle until oil pressure builds up and reapplies pressure to the tensioners and chain.

BMW seems to agree. They are changing my timing chain tensioners as we speak. However, another member posted that this didn't solve his problem. In one case, replacing the VANOS check valves seemed to do the trick but that didn't work in another. From what I understand, there are pins on the VANOS that lock the system in place when the engine is off in which case the check valves don't come into play at start up. Again, my dealer/BMW seems to agree with this. They disabled the VANOS system (disconnected the VANOS solenoid IIRC?) and the problem was still present.

edit: I should also mention that nothing suggests that this is a bearing issue.

It is a weird one. Before the engine was replaced in my car by BMW, they tried:

None worked. That was my car in particular of course - so it doesn't mean some of these ideas won't fix another.

Each time the foreman went through their next course of action with me, it sounded completely right and feasible - but never worked.

I hope they learnt was the issue was from taking apart my old engine and have formulated a plan to rid the noise in other cars in the future (should it show)

I wish that was true, but sadly, I don't think it is. The are doing the tensioners on mine as we speak. Thanks for your posts BTW! The worst thing about forums is that people don't report back with the solution and/or additional details.

I wish that was true, but sadly, I don't think it is. The are doing the tensioners on mine as we speak. Thanks for your posts BTW! The worst thing about forums is that people don't report back with the solution and/or additional details.